Spatial signalling schemes, such as ‘spatial modulation’ and ‘space-shift keying’ encode data onto the spatial signature of the channel. This is done through the selection of one or a plurality of antennas according to the data bits that are to be conveyed to an intended receiver.
In a spatial modulation scheme, part of the information to be transmitted is encoded by using a modulation technique such as Binary Phase Shift Keying (BPSK) modulation. The remaining part is used to specify which antenna of an array of antennas the BPSK symbol representing the first part is transmitted.
Space-shift keying is performed in an identical manner, but information is only conveyed using the channel signatures of the antennas, i.e., modulation schemes like BPSK are not used.